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Boilerplate/Win32: Switch to a DIB section
The Win32 boilerplated works by positioning a test HWND at (INT_MIN, INT_MIN) and drawing into the client HDC. However, the image read-back always yields a blank image (_cairo_boilerplate_get_image_surface). The window is positioned offscreen, thus GDI returns an HDC that is completely clipped, as GDI always clips to the visible region of the client area. In short, every drawing operation turns into a no-op. It's probably best to use a bitmap target with a memory DC. This commit reworks the Win32 boilerplate to target a DIB section.
This commit is contained in:
Luca Bacci
parent
d04906aad6
commit
bc84f415bb
1 changed files with 124 additions and 142 deletions
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@ -30,180 +30,162 @@
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#include <errno.h>
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#include <limits.h>
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#include <assert.h>
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static const cairo_user_data_key_t win32_closure_key;
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typedef struct _win32_target_closure {
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HWND wnd;
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HDC dc;
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ATOM bpl_atom;
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cairo_surface_t *surface;
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HBITMAP hbitmap; /* Bitmap */
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void *data; /* Bitmap data */
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HDC hdc; /* Memory DC with bitmap selected */
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} win32_target_closure_t;
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static void
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_cairo_boilerplate_win32_cleanup_window_surface (void *closure)
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_cairo_boilerplate_win32_cleanup_ddb_surface (void *closure)
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{
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win32_target_closure_t *win32tc = closure;
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if (win32tc != NULL)
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{
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if (win32tc->wnd != NULL &&
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ReleaseDC (win32tc->wnd, win32tc->dc) != 1)
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fprintf (stderr,
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"Failed to release DC of a test window when cleaning up.\n");
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if (win32tc->wnd != NULL &&
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DestroyWindow (win32tc->wnd) == 0)
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fprintf (stderr,
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"Failed to destroy a test window when cleaning up, GLE is %lu.\n",
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GetLastError ());
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if (win32tc->bpl_atom != 0 &&
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UnregisterClassA ((LPCSTR) MAKELPARAM (win32tc->bpl_atom, 0), GetModuleHandle (NULL)) == 0 &&
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GetLastError () != ERROR_CLASS_DOES_NOT_EXIST)
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fprintf (stderr,
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"Failed to unregister boilerplate window class, GLE is %lu.\n",
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GetLastError ());
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if (win32tc->hdc != NULL) {
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/* https://devblogs.microsoft.com/oldnewthing/20100416-00/?p=14313 */
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SelectObject (win32tc->hdc, CreateBitmap (0, 0, 1, 1, NULL));
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free (win32tc);
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if (!DeleteDC (win32tc->hdc)) {
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fprintf (stderr, "%s failed during cleanup\n", "DeleteDC");
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}
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}
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if (win32tc->hbitmap) {
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if (!DeleteObject (win32tc->hbitmap)) {
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fprintf (stderr, "%s failed during cleanup\n", "DeleteObject");
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}
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}
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free (win32tc);
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}
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}
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static win32_target_closure_t *
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_cairo_boilerplate_win32_create_window (int width,
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int height)
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{
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WNDCLASSEXA wincl;
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win32_target_closure_t *win32tc;
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LPCSTR window_class_name;
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ZeroMemory (&wincl, sizeof (WNDCLASSEXA));
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wincl.cbSize = sizeof (WNDCLASSEXA);
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wincl.hInstance = GetModuleHandle (0);
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wincl.lpszClassName = "cairo_boilerplate_win32_dummy";
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wincl.lpfnWndProc = DefWindowProcA;
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wincl.style = CS_OWNDC;
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win32tc = calloc (1, sizeof (win32_target_closure_t));
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if (win32tc == NULL)
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{
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int error = errno;
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fprintf (stderr, "Ran out of memory: %d.\n", error);
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return NULL;
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}
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ZeroMemory (win32tc, sizeof (win32_target_closure_t));
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win32tc->bpl_atom = RegisterClassExA (&wincl);
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if (win32tc->bpl_atom == 0 && GetLastError () != ERROR_CLASS_ALREADY_EXISTS)
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{
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fprintf (stderr,
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"Failed to register a boilerplate window class, GLE is %lu.\n",
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GetLastError ());
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_cairo_boilerplate_win32_cleanup_window_surface (win32tc);
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return NULL;
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}
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if (win32tc->bpl_atom == 0)
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window_class_name = wincl.lpszClassName;
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else
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window_class_name = (LPCSTR) MAKELPARAM (win32tc->bpl_atom, 0);
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win32tc->wnd = CreateWindowExA (WS_EX_TOOLWINDOW,
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window_class_name,
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0,
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WS_POPUP,
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0,
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0,
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width,
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height,
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0,
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0,
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0,
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0);
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if (win32tc->wnd == NULL)
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{
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fprintf (stderr,
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"Failed to create a test window, GLE is %lu.\n",
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GetLastError ());
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_cairo_boilerplate_win32_cleanup_window_surface (win32tc);
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return NULL;
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}
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win32tc->dc = GetDC (win32tc->wnd);
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if (win32tc->dc == NULL)
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{
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fprintf (stderr, "Failed to get test window DC.\n");
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_cairo_boilerplate_win32_cleanup_window_surface (win32tc);
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return NULL;
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}
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SetWindowPos (win32tc->wnd,
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HWND_BOTTOM,
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INT_MIN,
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INT_MIN,
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width,
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height,
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SWP_NOACTIVATE | SWP_SHOWWINDOW);
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return win32tc;
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}
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static cairo_surface_t *
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_cairo_boilerplate_win32_create_window_surface (const char *name,
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cairo_content_t content,
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double width,
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double height,
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double max_width,
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double max_height,
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cairo_boilerplate_mode_t mode,
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void **closure)
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_cairo_boilerplate_win32_create_ddb_surface (const char *name,
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cairo_content_t content,
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double width,
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double height,
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double max_width,
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double max_height,
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cairo_boilerplate_mode_t mode,
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void **closure)
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{
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win32_target_closure_t *win32tc;
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cairo_surface_t *surface;
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win32_target_closure_t *win32tc = NULL;
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cairo_format_t format;
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cairo_surface_t *surface;
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cairo_status_t status;
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WORD pixel_bits;
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struct {
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BITMAPINFOHEADER header;
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RGBQUAD color_table[256];
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} bitmap_desc = {0};
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HBITMAP hbitmap_old;
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win32tc = _cairo_boilerplate_win32_create_window (width, height);
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if (width < 1.0)
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width = 1.0;
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if (height < 1.0)
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height = 1.0;
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if (win32tc == NULL)
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return NULL;
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win32tc = calloc (1, sizeof (win32_target_closure_t));
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if (win32tc == NULL) {
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fprintf (stderr, "%s failed with errno %d\n", "calloc", errno);
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*closure = NULL;
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return NULL;
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}
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format = cairo_boilerplate_format_from_content (content);
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memset (win32tc, 0, sizeof (*win32tc));
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surface = cairo_win32_surface_create_with_format (win32tc->dc, format);
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*closure = win32tc;
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win32tc->surface = surface;
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switch (content) {
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case CAIRO_CONTENT_COLOR:
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format = CAIRO_FORMAT_RGB24;
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pixel_bits = 32;
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break;
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case CAIRO_CONTENT_COLOR_ALPHA:
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format = CAIRO_FORMAT_ARGB32;
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pixel_bits = 32;
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break;
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case CAIRO_CONTENT_ALPHA:
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format = CAIRO_FORMAT_A8;
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pixel_bits = 8;
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break;
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default:
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assert (0); /* not reached */
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format = CAIRO_FORMAT_INVALID;
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break;
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}
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if (pixel_bits <= 8) {
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assert (pixel_bits == 8);
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for (BYTE i = 0; i <= 255; i++) {
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bitmap_desc.color_table[i].rgbBlue = i;
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bitmap_desc.color_table[i].rgbGreen = i;
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bitmap_desc.color_table[i].rgbRed = i;
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bitmap_desc.color_table[i].rgbReserved = 0;
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}
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}
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assert (width < (double)LONG_MAX);
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assert (height < (double)LONG_MAX);
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bitmap_desc.header.biSize = sizeof (bitmap_desc.header);
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bitmap_desc.header.biWidth = (LONG)width;
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bitmap_desc.header.biHeight = -(LONG)height; /* a negative height tells GDI to
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use a top-down coordinate system */
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bitmap_desc.header.biPlanes = 1;
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bitmap_desc.header.biBitCount = pixel_bits;
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bitmap_desc.header.biCompression = BI_RGB;
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/* From https://learn.microsoft.com/en-us/windows/win32/api/wingdi/nf-wingdi-createdibsection:
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* CreateDIBSection does not use the parameters biXPelsPerMeter or biYPelsPerMeter */
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win32tc->hbitmap = CreateDIBSection (NULL, (BITMAPINFO*)&bitmap_desc, DIB_RGB_COLORS, &win32tc->data, NULL, 0);
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if (win32tc->hbitmap == NULL) {
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fprintf (stderr, "%s failed with error code %u\n", "CreateDIBSection", (unsigned int) GetLastError ());
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return NULL;
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}
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win32tc->hdc = CreateCompatibleDC (NULL);
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if (win32tc->hdc == NULL) {
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fprintf (stderr, "%s failed\n", "CreateCompatibleDC");
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return NULL;
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}
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hbitmap_old = SelectObject (win32tc->hdc, win32tc->hbitmap);
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assert (hbitmap_old == CreateBitmap (0, 0, 1, 1, NULL));
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surface = cairo_win32_surface_create_with_format (win32tc->hdc, format);
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status = cairo_surface_status (surface);
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if (status != CAIRO_STATUS_SUCCESS)
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{
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if (status != CAIRO_STATUS_SUCCESS) {
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fprintf (stderr,
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"Failed to create the test surface: %s [%d].\n",
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cairo_status_to_string (status), status);
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_cairo_boilerplate_win32_cleanup_window_surface (win32tc);
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cairo_surface_destroy (surface);
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_cairo_boilerplate_win32_cleanup_ddb_surface (win32tc);
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return NULL;
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}
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status = cairo_surface_set_user_data (surface, &win32_closure_key, win32tc, NULL);
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if (status != CAIRO_STATUS_SUCCESS)
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{
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if (status != CAIRO_STATUS_SUCCESS) {
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fprintf (stderr,
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"Failed to set surface userdata: %s [%d].\n",
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cairo_status_to_string (status), status);
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cairo_surface_destroy (surface);
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_cairo_boilerplate_win32_cleanup_window_surface (win32tc);
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cairo_surface_destroy (surface);
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_cairo_boilerplate_win32_cleanup_ddb_surface (win32tc);
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return NULL;
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}
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*closure = win32tc;
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return surface;
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}
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@ -228,7 +210,7 @@ _cairo_boilerplate_win32_create_dib_surface (const char *name,
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static const cairo_boilerplate_target_t targets[] = {
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{
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"win32", "win32", NULL, NULL,
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"win32-DIB", "win32", NULL, NULL,
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CAIRO_SURFACE_TYPE_WIN32, CAIRO_CONTENT_COLOR, 0,
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"cairo_win32_surface_create_with_dib",
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_cairo_boilerplate_win32_create_dib_surface,
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@ -242,11 +224,11 @@ static const cairo_boilerplate_target_t targets[] = {
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NULL,
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TRUE, FALSE, FALSE
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},
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/* Testing the win32 surface isn't interesting, since for
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* ARGB images it just chains to the image backend
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/* Testing the win32 surface for ARGB32 DIBs isn't interesting,
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* since it just chains to the image backend
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*/
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{
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"win32", "win32", NULL, NULL,
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"win32-DIB", "win32", NULL, NULL,
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CAIRO_SURFACE_TYPE_WIN32, CAIRO_CONTENT_COLOR_ALPHA, 0,
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"cairo_win32_surface_create_with_dib",
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_cairo_boilerplate_win32_create_dib_surface,
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@ -261,31 +243,31 @@ static const cairo_boilerplate_target_t targets[] = {
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FALSE, FALSE, FALSE
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},
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{
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"win32-window-color", "win32", NULL, NULL,
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"win32-DDB", "win32", NULL, NULL,
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CAIRO_SURFACE_TYPE_WIN32, CAIRO_CONTENT_COLOR, 1,
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"cairo_win32_surface_create",
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_cairo_boilerplate_win32_create_window_surface,
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_cairo_boilerplate_win32_create_ddb_surface,
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cairo_surface_create_similar,
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NULL,
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NULL,
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_cairo_boilerplate_get_image_surface,
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cairo_surface_write_to_png,
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_cairo_boilerplate_win32_cleanup_window_surface,
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_cairo_boilerplate_win32_cleanup_ddb_surface,
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NULL,
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NULL,
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FALSE, FALSE, FALSE
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},
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{
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"win32-window-coloralpha", "win32", NULL, NULL,
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"win32-DDB", "win32", NULL, NULL,
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CAIRO_SURFACE_TYPE_WIN32, CAIRO_CONTENT_COLOR_ALPHA, 1,
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"cairo_win32_surface_create_with_format",
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_cairo_boilerplate_win32_create_window_surface,
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_cairo_boilerplate_win32_create_ddb_surface,
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cairo_surface_create_similar,
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NULL,
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NULL,
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_cairo_boilerplate_get_image_surface,
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cairo_surface_write_to_png,
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_cairo_boilerplate_win32_cleanup_window_surface,
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_cairo_boilerplate_win32_cleanup_ddb_surface,
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NULL,
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NULL,
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FALSE, FALSE, FALSE
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